"The trailer offers a host of breathtaking footage, including snippets of Kun-Lun, the death of Danny's parents, plenty of martial arts action, the Meachum family, and the appearance of the enigmatic Madame Gao from Daredevil. Still no sign of that classic costume, but that will probably be saved for the series release.
from https://www.comicbookmovie.com/tv/marve ... or-a148767

Showrunner Scott Buck has come forward to explain why Danny won't be seen wearing his iconic green and yellow garb...

Buck said "there was no good reason" they could think to put him in that outfit. In the series, Rand "is still discovering who he is as a hero and where he is going to be." As such, he's "not yet ready to put on a mask or a costume."